fuel NISSAN 300ZX 1984 Z31 Engine Fuel And Emission Control System Workshop Manual

ENGINE FUEL &
- EMISSION - CONTROL SYSTEM
SECTION EFaEC
CONTENTS
PRECAUTIONS ..
COMPONENT PARTS LOCATION
ECCS DIAGRAM
. . .
ECCS CHART ..
ECC.S WIRING DIAGRAM . . ..
FUEL FLOW SYSTEM DESCRIPTION .
AIR FLOW SYSTEM DESCRIPTION ....
E C C S. DESCRIPTION . . . . ...
DIAGNOSTIC PROCEDURE . ..
SE LF-D I AGNOSIS ..
..
.. ..
..
..
..
...
ELECTRONfC CONTROL SYSTEM INSPECTION
MIXTURE RATIO FEEDBACK SYSTEM INSPECTION
. ,
FUEL SYSTEM INSPECTION
TURBOCHARGER
. ... ..
INJECTOR COOLING FAN (VG30ET) .
PRESSURE REGULATOR CONTROL
CRANKCASE EMISSION CONTROL SYSTEM
. . . .
EXHAUST EMISSION CONTROL SYSTEM . . ...
EVAPORATIVE EMISSION CONTROL SYSTEM . . .
SERVICE DATA AND SPECIFICATIONS (S DS). . . . . . .
. . EF&EC- 2
. EF&EC- 3
EF & EC- 4
EF&EC- 6
EF&EC- 8
.. EF & EC-10
EF
& EC-11
, EF&EC-13
EF
& EC-28
EF
& EC-35
EF
& EC43
EF & EC-60
EF
& EC-63
EF
& EC-66
EF
& EC-69
EF
& EC-72
. . EF & EC-74
EF
& EC-75
, EF&EC-76
EF & EC-79

PRECAUTIONS
Always use 12 volt batteries as * Do not disassemble E C C S When installing large capacity wire-
Do not attempt to disconnect Do not turn diagnosis mode sure to obsetve the following as it power source
battery cables while engine
IS
control unit
selector less equipment or a vehicle phone, be
may adversely affect electronic con-

operating
Do not apply battery power
directly to injectors
Do not remove the fuel tem-
perature sensor from
the T

pressure regulator
Replace as an assembly
trol systems depending on its installa-
tion location
1) Keep the antenna as far as possible
away from the electronic control
units
2) Also keep the antenna feeder line
more than
20 cm (7 9 in) away from
the harness of electronic controls
Do not let them run parallel for a
long distance
3) Adjust the antenna and feeder line so
that the standing-wave ratio can be
keot smaller
J
Handle air flow meter care-
fully to avoid damage * Do not disassemble auxiliary
Do not disassemble air flow air control valve (VG30ET
meter engine)
Do not clean air flow meter
with any type of detergent
0 Even a slight leak in the air in- /
&&%$$?&
take system can cause serious
problems
Do not depress accelerator Do not shock or jar the crank
angle sensor
Immediately after starting, do
pedal when starting
not rev
up engine unneces-
sarily
Do not rev up engine just prioi
to shutdown
Do not operate fuel pump when
there is no fuel in lines Do not use anti-freeze agents in fuel
0 Do not reuse fuel hose clamps
0 Tighten fuel hose clamps sufficiently
Securely connect E C C S harness
connectors
A poor connection can cause an ex-
tremely
high (surge) voltage to
develop in coil and condenser, thus
resulting in damage to IC circuit
Keep
E C C S harness at least 10 cm
(3 9 in) away from adjacent
harnesses, to prevent an
E C C S
system malfunction due to reception
of external noise, degraded operation
of
IC circuit. etc
Keep E C C S parts and harnesses
Before removing parts, turn off igni-
tion switch and then disconnect
battery ground cable dry
SEF6008
EF & EC-2

E.C.C.S. CHART
Exhaust gas sensor t
b
Throttle valve switch -b
VG30E Engine (Without turbocharger)
ECCS
control
unit
Crank angle sensor
%el pump control Fuel pump
Air conditioner switch 1 t
Battery voltage
- I
Injectors Fuel injection &
mixture ratio control
VI 1
1
Ignition timing control Power transistor
Idle-up control Idle-up solenoid valve
E G R control E G R control solenoid valve
-1 I
Inspection lamps ixhaust gas sensor
nonitor
& self-diamosis
EF & EC-6

E. C. C.S. CHART
VG30ET Engine (With turbocharger)
Air flow meter c
Cylinder head temperature sensor b
b
Ignition switch b
Throttle valve switch I b
b
Park/Neutral switch
Air conditioner switch I
b
E C C.S
control
unit
b
Injectors Fuel injection &
mixture ratio control
--I
Ignition timing control Power transistor
-dI Auxiliary air control
(A A
C ) valve Idle speed control
I YL
E G R control E G R control solenoid valve
Fuel pump control Fuel pump
Inspection lamps ixhaust gas sensor
nonitor
& self diagnosis I
EF & EC-7

FUEL FLOW SYSTEM DESCRIPTION
The amount of fuel to be injected is determined by
the injection pulse duration
as well as by a pressure
difference between fuel pressure and intake mani-
fold vacuum pressure. The
E.C C.S. control unit
controls only the injection pulse duration For this
reason,
the pressure difference between the fuel
pressure and intake manifold vacuum pressure
should be maintained
at a constant level Since the
intake manifold vacuum pressure varies with engine
operating conditions,
a pressure regulator IS placed
in the fuel line to regulate the fuel pressure in
response to changes
in the intake manifold vacuum
pressure
Fuel pump and damper
’ iFueirank
SEF604B
intake manifold 0 vacuum
a From fuel tank
Fuel chamber
SEF605B
Fuel presswe
EF & EC-10

E.C.C.S. DESCRIPTION
E.C.C.S.
E C C.S. CONTROL UNIT
The E C C S control unit consists of a micro-
computer, connectors for signal input and output
and power supply, inspection lamps and diagnostic
mode selector The control unit controls the
amount
of fuel that is injected, ignition timing, idle
speed,
E G R , fuel pump operation, and feedback
of the mixture ratio
SEF611 B
CRANK ANGLE SENSOR
Crank angle sensor is a basic signal sensor for the
entire
E C C S It monitors engine speed and piston
position, and
it sends signals to the E C C S con-
trol unit for control of
fuel injection, ignition
timing, idle speed, fuel pump operation and
E G R
operation.
rnponents
Crank angle sensor has rotor plate and wave form-
ing circuit Rotor plate has
360 slits for 1" signal
(engine speed signal) and
6 slits for 120" signal
(crank angle signal) Light Emitting Diodes
(L
E D ) and Photo Diodes are built into wave
forming circuit
When
signal rotor plate passes the space between
the
L E D and Photo Diode, the slit of the signal
rotor plate alternately cuts the light which
is sent
to
the photo diode from the L E D This causes an
alternative voltage and
it is then converted into an
on-otf pulse by the wave forming circuit, which IS
sent to the control unit
Sealed mwr
Rotor head
.-- ? Lighremitring -. - diode 'I- 1- . ;-- , -
. A. -7. l.lll- i:--, .J
- I -, _,- I- ..
. ir- .I
4,,
Phatodlodel fi-. h- 1 ,h
Wave forming-' circurt '-Rotor piate
SEFBlJB
Rotor plate
SEF614B
EF & EC-13

E. C. C. S. DESCRIPTION
E.C.C.S. Corn
FUEL TEMPERATURE SENSOR
The fuel temperature sensor is built into the pres-
sure regulator, and senses fuel temperature When
the fuel temperature
IS higher than the specified
level, the
E C C S control unit enriches fuel inject-
ed
Pressure regulator
Fuel temprature $ens
SEF625B
Do not remove fuel temperature sensor from pres-
sure regulator. Always replace as
an assembly.
DETONATION SENSOR (VG30ET engine only)
The detonation sensor
is attached to the cylinder
block and senses engine knocking conditions
A knocking vibration from the cylinder block is
applied as pressure to the piezoelectric element
This vibrational pressure
IS then converted into a
voltage signal which is delivered as output
Reed plate ,, ,-Weight
rTerminal
-.
Piezoelectric element
SEFSZSB
/-
FUEL INJECTOR
The
fuel injector is a small, precision solenoid
valve As the
E C C S control unit outputs an in-
lnents (Cont’d)
jection signal to each fuel injector, the coil built
into the injector pulls the needle valve back, and
fuel
is injected through the nozzle to intake mani-
fold The amount of fuel injected
is controlled by
the
E C C S control unit as an injection pulse
duration
<-Nozzle

LNeedle valve
SEF627B
POWER TRANSISTOR
The ignition signal from the
E C C S control unit
is amplified by the power transistor, which con-
nects and disconnects the coil primary circuit to
induce the proper high voltage in the secondary
circuit
SEFSZBB
IGNITION COIL
The ignition coil
IS a mold type
EF & EC-17

E. C. C. S. DESCRIPTION
E.C.C.S. Components (Cont’d)
E.G.R. CONTROL SOLENOID VALVE
E G R control solenoid valve cuts intake manifold
vacuum signal for
E G.R control The solenoid
valve actuates in response to the ON/OFF signal
from
the E C.C S control unit. When the solenoid
is off, vacuum signal from intake manifold is fed
into the
E G R control valve As the control
unit outputs an ON signal, the coil pulls the
plunger downward, and cuts the vacuum signal
9 Atmosphere
ToEGR control valve
From intake
SEF6336 0 manifold
FUEL PUMP
The fuel pump, which is located in the fuel tank, IS
a wet type pump where the vane rollers are directly
coupled to
a motor which is filled with fuel
1 Outlet A
AIR REGULATOR
Air regulator gives an air by-pass when the engine is
cold for the purpose of a fast idle during warm-up
SE F635 B
A bimetal, heater and rotary shutter are built into
the air regulator When the bimetal temperature
IS
low,
the air by-pass port is open As the engine
starts and electric current flows through a heater,
the bimetal begins to rotate the shutter
to close off
the by-pass port The air passage remalns closed
until the engine
is stopped and the bimetal tem-
perature drops
SEF636B
EF & EC-19

E.C.C.S. DESCRIPTION
Fuel Injection Control
Temperature of engine Cylinder head temperature sensor
Density of oxygen in exhaust gas Exhaust gas sensor
Throttle valve idle position ' Throttle valve switch
Engine speed and piston position
Amount of intake air Air flow meter
ECCS
I I
I
control
Gear position unit NeutraVPark switch (VG30ET) I I
Vehicle speed
Start signal
Temperature of fuel
Battery voltage Battery
The E.C C S control unit calculates basic injection
pulse
width by processing signals from crank angle
sensor and air flow meter Receiving signals from
each sensor which detects various engine condi-
tions,
E C.C S control unit adds various enrich-
ments, which are pre-programmed
in the control
unit, to the basic injection amount. Thus, the op-
timum amount of fuel is injected through the
injectors.
1 ) Fuel enrichment
In the following each conditions, fuel is
enriched
e During warm-up
When starting
After idle
e When accelerating
e With heavy load
e When fuel temperature is high
.I Injector
Rlch
' \/ .-Warm-u~ enrichment
Cylmder head temperature (or fuel temperature1 SE F637 0
Enrichment rates for "when accelerating" and
"with heavy load" are pre-programmed for engine
speed and basic injection pulse
width
EF & EC-20

E. C. C. S. DESCRIPTION
Deceleration from @
Deceleration from @
Deceleration from 0 or @
Fuel Injection
2) Fuel shut-off
Fuel shut-off is accomplished under the follow-
ing conditions.
a During deceleration
@ and @ 62
0 (E9
- -
- -.. . . . ._ '. .
VG30ET (MITI
VG30E
_-- VGXIET IA/Tl
-20 0 20 40 60 SO 100
(-41 1321 (681 11041 (1401 (1761 12121
Cvlinder head IemPerature "C 1°F)
SEF638B
b High engine speed
When engine speed is more than 6,500 rpm,
fuel
is shut-off for safety reasons
High vehicle speed
(VG30ET engine only)
When vehicle speed
is more than 220 km/h
(137 MPH), fuel is shut-off for safety reasons
c
mtrol (Cont'd)
3) Mixture ratio feedback control
Mixture ratio feedback system is designed to
control the mixture ratio precisely to the
*stoichiometric point
so that the three-way
!catalyst can minimize
CO, HC and NOx emis-
';ions simultaneously This system
uses exhaust
gas senwr located in the exhaust manifold to
give an indication of whether the air-fuel ratio
is richer or leaner than the stoichiometric
point The control unit adjusts the injection
pulse width according to the sensor voltage so
the mixture ratio will be within the narrow
window around the stoichiometric
air fuel
ratio
eontroi
Injector
0
Combustm
Engme
However, this system will open under the
following conditions
When starting engine.
When engine and exhaust
gas sensor is cold
When driving
at high speeds or under heavy
load.
At idle
When exhaust
gas sensor monitors a too lean
condition for more than
10 seconds.
When fuel shut-off
is in omration
EF & EC-21